Soluble imide-quinoxaline copolymers

ABSTRACT

PHENYLATED IMIDE QUINOXALINE CO-POLYMERS CONSISTING ESSENTIALLY OF UNITS OF THE FORMULA   -(2-PHENYL-3,6-QUINOXALINYLENE)-X-(2-PHENYL-6,3-   QUINOXALINYLENE)-R-N(-CO(-))-CO-Y-CO-N(-CO(-))-R)-   WHERE THE CO(-)&#39;&#39;S ARE ALSO JOINED TO Y   WHEREIN X IS A DIRECT BOND   O, S, SO, SO2 OR -CO-   R IS M OR P-PHENYLENE AND Y IS   (BENZENE-4,3,1-TRIYL)-CO-(BENZENE-1,3,4-TRIYL) OR   TETRAHYDROFURAN-2,3,4,5-TETRAYL   WHICH ARE USEFUL AS COATINGS FOR FIBERS, GRAPHITE PRECURSORS, FILMS AND LAMINATING MATERIALS ARE PREPARED BY CONTACTING   1-((3,4-DI(H2N-)-PHENYL)-X-),3,4-DI(NH2-)BENZENE   WITH   1-((3-((4-(PHENYL-CO-CO-)PHENYL)-N(-CO(-))-CO-Y-CO-N(-CO-   (-))-)PHENYL)-CO-CO-)BENZENE WHERE CO(-)&#39;&#39;S ARE ATTACHED   TO Y   1-((3-((3-(PHENYL-CO-CO-)PHENYL)-N(-CO(-))-CO-Y-CO-N(-   CO(-)-)PHENYL)-CO-CO-)BENZENE WHERE THE CO(-)&#39;&#39;S ARE   ATTACHED TO Y

United States Patent 3,654,226 SOLUBLE IMIDE-QUINOXALINE COPOLYMERSJoseph M. Augl, Sterling, Va., and James V. Duffy, Beltsville, Md.,assignors to the United States of America as represented by theSecretary of the Navy No Drawing. Filed Mar. 26, 1971, Ser. No. 128,524Int. Cl. C08g 33/02 US. Cl. 26050 10 Claims ABSTRACT OF THE DISCLOSUREPhenylated imide quinoxaline co-polymers consisting essentially of unitsof the formula wherein X is a direct bond,

R is m or p-phenylene and Y is 3,654,226 Patented Apr. 4, 1972BACKGROUND OF THE INVENTION This invention relates generally to polymersand more particularly to phenylated imide-quinoxaline copolymers.

Phenylated polyquinoxalines are known and have been disclosed incopending application Ser. No. 876,572, filed Nov. 13, 1969 entitledPhenylated Polyquinoxalines and Method of Preparation Thereof byWolfgang J. Wrasidlo. Phenylated imide-quinoxaline copolymers are alsoknown and have been disclosed in copending application Ser. No. 75,248,filed Sept. 24, 1970 entitled Phenylated Imide-Quinoxaline Copolyrnersand Method of Their Preparation by Joseph M. Augl. Such polymers areknown to have good oxidative thermal stability. Additionally some ofthese polymers, even those with a relatively high molecular weight, arevery soluble in common organic solvents. Since these polymers can beused as coatings, it is highly desirable that they be easily removed bycontacting with common organic solvents so that it is possible to easilyinspect or repair materials which have been coated with them.Furthermore, polymer coatings of the prior art often have to be heatcured before they can be used thereby requiring an additional step inorder to use them elfectively. A continuing search goes on for polymerswhich do not require a heat cure, which can be used as coatings andwhich have good oxidativethermal stability as well as good-solubility incommon organic solvents.

SUMMARY OF THE INVENTION Accordingly, one object of this invention is toprovide phenylated imide-quinoxaline copolymers.

Another object of this invention is to provide phenylatedimide-quinoxaline copolymers which have excellent oxidative-thermalstability.

A still further object of the instant invention is to provide phenylatedimide-quinoxaline copolymers which can be used as high temperatureprotective coatings for fibers, graphite precursors, films andlaminating materials.

Yet another object of the present invention is to provide a phenylatedimide-quinoxaline copolymer which requires no heat cure before usebecause of imide ring formation prior to polymerization.

A further object of this invention is to provide starting materials fromwhich the phenylated imide-quinoxaline copolymers of this invention canbe prepared.

These and other objects of this invention are accomplished by providingcopolymers consisting essentially of units of the formula 4 wherein X isselected from the group consisting of a the amino analogue VIII, VII istreated with an acid. direct bond, VIII is then converted to III byreaction with a compound of Formula IX. S. S S 02am ll The polymer isprepared by reacting in a solvent, such 0 5 as m-cresol, the tetraamineof Formula II with the com- R is Selected from the group consisting ofI11 and P- pounds of Formula IH or IV. This reaction may be conphenyleneand Y is selected from the group consisting of d ted entirely at roomtemperature or at a somewhat elevated temperature. It is desirable,though not neces- O sary, to raise the temperature to above 100 C. for afew minutes at the end of the reaction in order to drive out the C and 0water that has formed during the reaction.

The general nature of the invention having been set which are preparedby contacting forth, the following examples are presented as specificillustrations thereof. It will be understood that the inven- 15 tion isnot limited to these specific examples but is susceptible to variousmodifications that will be recognized by one of ordinary skill in theart.

H Example 1 Wlth 2O 4'-aminodeoxybenzoin o 0 0 o 0 II II 0 0 II I] Y Amixture of 64.0 g. of 4'-nitrodeoxybenzoin, 40.0 g. of 0- iron powder,3.5 ml. of concentrated hydrochloric acid, a k J m 500 ml. of ethanol,and 250 ml. of water was refluxed for one hour. The hot solution wasfiltered and the filtrate when R is p-phenylene and with was poured into1.5 liters of water, giving a slight yellow 0 0 3O precipitate, M.P.95-7 C. 0 C l 0 Example 2 o L- N Y N- 7-( 4-acetamidodeoxybenzoin T T nI g IV AeNH@-OH2 C@ when R is m-phenylene. A mixture of 20.0 g. of4'-aminodeoxybenzoin, 50 ml. DESCRIPTION OF THE PREFERRED of glacialacetic acid, and 50 ml. of acetic anhydride was EMBODIMENT heated atreflux for two hours. The solution was then 40 poured 1nto one liter ofwater, giving a white solid which The Phenylated imide-quinoxalillecopolymers of this was recrystallized from a mixture of ethanol-water(1:1), invention are prepared by reacting compounds of For- M.P. 158160C. mula II with compounds of Formula III when R is to be E l 3p-phenylene and with compounds of Formula IV when R is to bem-phenylene. The reaction sequence that is used to prepare compounds ofFormula III is depicted as H II fo11ows= o o 4acetamidobenzil ll J l Amixture of 18.0 g. of 4'-acetamidodeoxybenzoin, 8.5 g. of seleniumdioxide, and 200 m1. of glacial acetic acid When compounds of Formula IVare desired the reaction sequence is identical except that NO; washeated at reflux for two hours and then filtered. Then 0 the mixture waspoured into one liter of water. The yield @0 H of 4-acetamidobenzilmonohydrate was 20.0 g. After two recrystallizations from benzene, thesolid was dehydrated, is the initial starting material. The first stepin the M.P. 1368 C.

sequence is the reduction of the nitro group to the amino Example 4group by any of the conventional reduction techniques,

such as, for example, treatment with iron in an acid solu- 7O4'ammobenzll tion, to obtain V. The amino compound obtained is then Oacylated by reaction with acetic anhydride in the con- HZN-@-c-lventional manner to obtain VI. Once acylated the compound is treatedwith selenium dioxide to oxidize the A mixture of 4-acetamidobenzil(15.0 g.) and 150 ml.

methylene group to a carbonyl to obtain VII. To form of concentratedhydrochloric acid was refluxed for four hours. The solid was filteredand made basic with sodium hydroxide to obtain the free base. Theprecipitated solid was recrystallibed from ethanol-water (1:1) to give12.1 g. of 4-aminobenzil, a pale yellow solid, M.P. l27-9 C.

Example 7 All the polymers of this invention listed in the followingtable were prepared in the same manner. Equimolar amounts of theappropriate constitutents, preferably about Example r 0.001 mole ofeach, were stirred under nitrogen in m-N,N-bis(4-benzilyl-3,3,4,4'-benzophenonecresol. In all cases a by weightsolution was used. tetracarboxylimide The temperature was kept between90-100 C. for from A mixture of 4-aminobenzil, 2.87 g. of3,3',4,4-benzophenonetctracarboxylic dianhydride and ml. ofdimethylacetamide was stirred under nitrogen for 16 hours at roomtemperature. At this point, 8 ml. of acetic anhydride and 2 ml. ofpyridine were added, and the mixture was then refluxed for 8 hours.After the first 5 hours Polymer de Polymer of Formula I, wherein X, Rand Y are- Inherent composition viscosity 1 tempera- X R Y (dl./g.) tureI C.)

1 Direct bond p-Phenylene 1. 54 630 2 --C- do Same as above 0.78 525 3S01 .do do 0.62 490 4 0 do ..do 1.09 515 5 Direct bond .do l 2 07 290 6(fi --.do Same as above 1.02 810 7 80; do do 1.24 300 8 0 do do 2.11 320X Determined as a 0.5 g. in 100 m1. m-cresol solution at 30 C.

Determined from TGA data in vacuum at a heating rate of 5 0. per minute.

of reflux, 2 ml. more of pyridine were added. A light yellow solidprecipitated which was filtered and washed with a 1,1 mixture ofhexane-acetone. The yield was 4.0 g., M.P. 2801 C.

Example 6 N,N-bis(4-benzilyl)tetrahydrofuran-tetraoarboxylimide Thepolymers of this invention have an inherent viscosity of between about0.4 to 3.0 dl./g. in m-cresol (0.5 g. in 100 ml. at 30 C.). For laminatecoatings a viscosity of between about 0.4-0.9 is preferred while forfilms and fibers a viscosity as high as possible is preferred.

To obtain the relatively high viscosities, it is only neces- A mixtureof 4.0 g. of 4-aminobenzil, 1.89 g. of tetrahydrofurantetracaroxylicdianhydn'de was stirred under nitrogen for 16 hours at room temperture.A total of 8 ml. of acetic anhydride and 2 m1. of pyridine were thenadded and the temperature was maintained at 75-80 C. for a period of 4hours. After cooling, the solution was poured into 400 ml. of water togive a bright lemon yellow colored solid. Yield 2.0 g., M.P. 279-80 C.

sary to use very pure materials. These copolymers are also relativelysoluble in solvents such as m-cresol, m-

methoxyphenol, tetrachloroethane, chloroform, dimethylacetamide,N-methylpyrrolidone, hexafi-uoroacetone, hexafluoroisopropanol,nitrobenzene, and pyridine.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims theinvention may be practiced otherwise than as specifically describedherein. What is claimed as new and desired to be secured by LettersPatent of the United States is:

1. Phenylated irnide-quinoxaline copolymers consisting essentially ofunits of the formula to o! K X N -R-N\ Y /NR L FT 7 J wherein X isselected from the group consisting of a direct bond,

R is selected from the group consisting of m and p-phenylene and Y isselected from the group consisting of i a... U

and having an inherent viscosity of between about 0.4 and 3.0 dl./g. asa solution of 0.5 g. of copolymer in 100 ml. m-cresol at 30 C.

2. A phenylated imide-quinoxaline copolymer according to claim 1 whereinX is selected from the group consisting of a direct bond,

0, SO: and fi and R is p-phenylene.

3. A phenylated imide-quinoxaline copolymer according to claim 2 whereinX is a direct bond and Y is 4. A phenylated imide-quinoxaline copolymeraccording to claim 2 wherein X is and Y is 5. A phenylatedimide-quinoxaline copolymer according to claim 2 wherein X is S0 and Yis 6. A phenylated imide-quinoxaline copolymer according to claim 2wherein X is O and Y is 7. A phenylated imide-quinoxaline copolymeraccording to claim 2 wherein X is a direct bond and Y is 8. A phenylatedimide-quinoxaline copolymer according to claim 2 wherein X is 9. Aphenylated imide-quinoxaline copolymer according to claim 2 wherein X isS0 and Y is 10. A phenylated imide-quinoxaline copolymer according toclaim 2 wherein X is O and Y is References Cited UNITED STATES PATENTS4/1970 Hoyt et a1 260 OTHER REFERENCES and Y is WILLIAM H. SHORT,Primary Examiner L. L. LEE, Assistant Examiner US. Cl. X.R.

l17l6l UN; 161-257; 26030.2, 30.6 R, 32.4, 32.6 N, 32.8 N, 33.4 R, 33.4P, 33.8 R, 63 N, 65, 326 N, 326.3

UNITED STATES PATENT OFFECE QERTIFICATE OF awesome:

i v 1 Page 3,654,226 Dated APrll 1972 InJentOflS) Joseph M. Augl andJames V. Duffy It is certified that error appears in the aboveidentifiedpatent ani that said Letters Patent are hereby corrected as shown below:

1 In Claim 1, Column 7, lines 18-19, between "s." and "$0 add --soSigned and sealed this 9th day of January 1973 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

